Protein Hydration Investigations with High-Frequency Dielectric Spectroscopy

Wei, Yubin; Kumbharkhane, A.C.; Sadeghi, Morteza; Sage, J. Timothy; Tian, W.; Champion, P. M.; Sridhar, Srinivas; McDonald, Matthew

doi:10.1021/j100077a034

Cited by 48 publications

(53 citation statements)

References 11 publications

(14 reference statements)

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“…Whereas to our knowledge the relaxational dynamics of water molecules in the solvation shell of electrolyte ions have not been characterized, one may speculate that the solute ion and the water molecules in the solvation shell form an entity with relaxation dynamics distinctly different from the relaxation dynamics of free water, as observed in studies of large solvated molecules [22][23][24]. In the case of very high electrolyte concentration, the relaxation dynamics should again be described by a single entity since the distinction between free and bound water vanishes.…”

Section: Resultsmentioning

confidence: 87%

Terahertz Reflection Spectroscopy of Aqueous NaCl and LiCl Solutions

Jepsen

Merbold

2009

J Infrared Milli Terahz Waves

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We present spectroscopic measurements of the full dielectric function of aqueous solutions of sodium chloride and lithium chloride at concentrations approaching their solubility limits at room temperature. We find that the dielectric properties of the two salts are rather different at THz frequencies. Whereas both the real and imaginary part of the permittivity of NaCl increases with concentration, we see that the imaginary part of the permittivity of LiCl (related to the absorption) decreases with increasing salt concentration. We relate these changes to the behavior of slow and fast Debye relaxation processes in the solutions.

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Section: Resultsmentioning

confidence: 87%

Terahertz Reflection Spectroscopy of Aqueous NaCl and LiCl Solutions

Jepsen

Merbold

2009

J Infrared Milli Terahz Waves

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“…To be observable against the background of bulk water (some 10 4 bulk water molecules at a protein concentration of 5 mM), the ␦ dispersion must then be attributed to a large number of hydration water molecules (in the order of 10 2 ). Many DRS studies have thus concluded that a sizeable fraction (typically, about one-half) of the water molecules in the hydration layer are strongly rotationally retarded, with ͗ hyd ͘/ bulk in the range of 10 2 -10 3 (Dachwitz et al 1989;Pethig 1992Pethig , 1995Miura et al 1994;Wei et al 1994). This conclusion is grossly inconsistent with the MRD results (see § 5a), yielding ͗ hyd ͘/ bulk Ϸ 2 for the vast majority of water molecules in the hydration layer.…”

Section: Other Spectroscopic Probes Of Hydration Dynamicsmentioning

confidence: 99%

Protein hydration dynamics in solution: a critical survey

Halle

2004

Phil. Trans. R. Soc. Lond. B

499

576

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The properties of water in biological systems have been studied for well over a century by a wide range of physical techniques, but progress has been slow and erratic. Protein hydration-the perturbation of water structure and dynamics by the protein surface-has been a particularly rich source of controversy and confusion. Our aim here is to critically examine central concepts in the description of protein hydration, and to assess the experimental basis for the current view of protein hydration, with the focus on dynamic aspects. Recent oxygen-17 magnetic relaxation dispersion (MRD) experiments have shown that the vast majority of water molecules in the protein hydration layer suffer a mere twofold dynamic retardation compared with bulk water. The high mobility of hydration water ensures that all thermally activated processes at the protein-water interface, such as binding, recognition and catalysis, can proceed at high rates. The MRD-derived picture of a highly mobile hydration layer is consistent with recent molecular dynamics simulations, but is incompatible with results deduced from intermolecular nuclear Overhauser effect spectroscopy, dielectric relaxation and fluorescence spectroscopy. It is also inconsistent with the common view of hydration effects on protein hydrodynamics. Here, we show how these discrepancies can be resolved.

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“…Thus the exact recognition of bulk water itself and the technique to detect tiny perturbation of response function by solute molecules are required. The progress of these researches have been made and numerous experimental and theoretical studies in microwave region have been published [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Terahertz time-domain attenuated total reflection spectroscopy in water and biological solution

Nagai

Yada

Arikawa

et al. 2006

Int J Infrared Milli Waves

147

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We demonstrate time-domain attenuated total reflection spectroscopy in terahertz frequency region. Geometry of the reflection measurement is well optimized to obtain accurate optical constants of water or aqueous biomolecular system. We determine the dielectric constants of distilled water and sucrose solutions with this technique. This technique will open new aspects in the research field of biological systems in water.

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Protein Hydration Investigations with High-Frequency Dielectric Spectroscopy

Cited by 48 publications

References 11 publications

Terahertz Reflection Spectroscopy of Aqueous NaCl and LiCl Solutions

Terahertz Reflection Spectroscopy of Aqueous NaCl and LiCl Solutions

Protein hydration dynamics in solution: a critical survey

Terahertz time-domain attenuated total reflection spectroscopy in water and biological solution

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